In recent years, methods of examining and diagnosing diseases based on the characteristics of cells have been developed. Thus, technology of rapidly and accurately measuring the characteristics of a small amount of cells has been required, and for this purpose, microfluidic devices have been introduced. Particularly, because the amount of heat generated from cancer cells and the like is about 1,000 times higher than that from normal cells, it is possible to early diagnose diseases such as cancer by measuring the amount of heat generated from cells. In addition, the activity of cells can be determined by measuring the amount of heat generated from tissue cells, and furthermore, the reaction rate and step can be determined by measuring the difference in the amount of generated heat between enzymes. Meanwhile, the amount of heat generated in cellular or enzymatic reactions is very low, and in order to accurately measure the amount of heat generation using a microfluidic device, the influence of an external environment should be removed and the influence of heat dissipation by convection during the flow of microfluids should be minimized. In addition, the amount of heat generated from cells should be measured in a state in which the cells are suspended in medium, so that the activity and survival time of the cells can be increased to ensure the accurate measurement of the amount of heat generated from the cells.
A sensor for measuring the amount of heat generated from cells according to the prior art is configured such that cells and medium are passed through a single microfluidic flow channel and a heat generation-measuring unit composed of a thermopile. In the prior art sensor for measuring the amount of heat generated from cells, medium and cells are injected through the single microfluidic flow channel. Thus, cells and medium are likely to be influenced by external noise caused by a change in atmospheric temperature, and convection heat dissipation in the heat generation-measuring unit by the flow of the medium occurs, making it difficult to accurately measure the amount of heat generated from the cells. Moreover, the convection heat transfer coefficient changes depending on the injection rates of medium and cells, and this change exerts an influence upon a signal for measuring the amount of heat generated. To overcome these shortcomings, the prior art sensor for measuring the amount of heat generated from cells requires a chamber, the temperature of which can be precisely controlled, and an ultra-low-flow rate fluid pump for controlling flow rate at a level of nl/min. In addition, to compensate for the temperature of the cold region of the thermopile, an assistant heater is required in addition to a main heater.